Electronic device for signaling a sub-picture buffer parameter

ABSTRACT

An electronic device for sending a message is described. The electronic device includes a processor and instructions stored in memory that is in electronic communication with the processor. The electronic device determines whether a picture is allowed to be decoded on a sub-picture level. If the picture is allowed to be decoded on a sub-picture level, the electronic device generates at least one of a buffer size parameter and a buffer scale parameter. The electronic device sends at least one of the buffer size parameter and the buffer scale parameter.

CROSS REFERENCE

This application is Continuation of co-pending application Ser. No.13/631,720 filed on Sep. 28, 2012, the entire contents of which arehereby incorporated by reference and for which priority is claimed under35 U.S.C. §120.

TECHNICAL FIELD

The present disclosure relates generally to electronic devices. Morespecifically, the present disclosure relates to electronic devices forsignaling a sub-picture parameter.

BACKGROUND

Electronic devices have become smaller and more powerful in order tomeet consumer needs and to improve portability and convenience.Consumers have become dependent upon electronic devices and have come toexpect increased functionality. Some examples of electronic devicesinclude desktop computers, laptop computers, cellular phones, smartphones, media players, integrated circuits, etc.

Some electronic devices are used for processing and displaying digitalmedia. For example, portable electronic devices now allow for digitalmedia to be consumed at almost any location where a consumer may be.Furthermore, some electronic devices may provide download or streamingof digital media content for the use and enjoyment of a consumer.

The increasing popularity of digital media has presented severalproblems. For example, efficiently representing high-quality digitalmedia for storage, transmittal and rapid playback presents severalchallenges. As can be observed from this discussion, systems and methodsthat represent digital media efficiently with improved performance maybe beneficial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of one or moreelectronic devices in which systems and methods for signaling asub-picture buffer parameter may be implemented;

FIG. 2 is a flow diagram illustrating one configuration of a method forsending a sub-picture buffer parameter;

FIG. 3 is a flow diagram illustrating a more specific configuration of amethod for sending a sub-picture buffer parameter;

FIG. 4 is a flow diagram illustrating another more specificconfiguration of a method for sending a sub-picture buffer parameter;

FIG. 5 is a flow diagram illustrating one configuration of a method forreceiving a sub-picture buffer parameter;

FIG. 6 is a block diagram illustrating one configuration of an encoderon an electronic device;

FIG. 7 is a block diagram illustrating one configuration of a decoder onan electronic device;

FIG. 8 illustrates various components that may be utilized in atransmitting electronic device;

FIG. 9 is a block diagram illustrating various components that may beutilized in a receiving electronic device;

FIG. 10 is a block diagram illustrating one configuration of anelectronic device in which systems and methods for sending a sub-picturebuffer parameter may be implemented; and

FIG. 11 is a block diagram illustrating one configuration of anelectronic device in which systems and methods for receiving asub-picture buffer parameter may be implemented.

DETAILED DESCRIPTION

An electronic device for sending a message is described. The electronicdevice includes a processor and instructions stored in memory that is inelectronic communication with the processor. The electronic devicedetermines whether a picture is allowed to be decoded on a sub-picturelevel. If the picture is allowed to be decoded on a sub-picture level,the electronic device generates at least one of a buffer size parameterand a buffer scale parameter. The electronic device sends at least oneof the buffer size parameter and the buffer scale parameter.

The buffer scale parameter may be a sub-picture coded picture buffer(CPB) size scale parameter. The sub-picture CPB size scale parameter maybe du_cpb_size_scale.

The buffer size parameter may be a sub-picture CPB size value parameter.The sub-picture CPB size value parameter may bedu_cpb_size_value_minus1[SchedSelIdx]. SchedSelIdx may be an indexvariable.

The buffer scale parameter may be a sub-picture CPB size scaleparameter. The sub-picture CPB size scale parameter may bedu_cpb_size_scale.

If the picture is allowed to be decoded on a sub-picture level, theelectronic device may generate a sub-picture CPB present parameter andsend the sub-picture CPB present parameter. The sub-picture CPB presentparameter may be a sub-picture CPB parameter present flag. Thesub-picture CPB parameter present flag may besub_pic_cpb_params_present_flag.

If the picture is allowed to be decoded on a sub-picture level, theelectronic device may perform a bitstream conformance test on thesub-picture level. An encoder may not violate the sent buffer sizeparameter and/or the sent buffer scale parameter.

An electronic device for testing a bitstream is also described. Theelectronic device includes a processor and instructions stored in memorythat is in electronic communication with the processor. The electronicdevice receives data. The electronic device also obtains a sub-picturelevel coded picture buffer (CPB) parameter. The electronic deviceperforms a sub-picture level CPB operation based on the sub-picturelevel CPB parameter.

Performing a sub-picture level CPB operation based on the sub-picturelevel CPB parameter may include performing an interpolated deliveryschedule test for sub-picture level CPB operation based on thesub-picture level CPB parameter. Performing a sub-picture level CPBoperation based on the sub-picture level CPB parameter may be based thespecification of a hypothetical reference decoder (HRD) operation.

Obtaining the sub-picture level CPB parameter may include obtaining asub-picture CPB size scale parameter. The sub-picture CPB size scaleparameter may be du_cpb_size_scale.

A method for sending a buffer parameter is also described. It may bedetermined whether a picture is allowed to be decoded on a sub-picturelevel. If the picture is be allowed to be decoded on a sub-picturelevel, a buffer size parameter and/or a buffer scale parameter isgenerated. The buffer size parameter and/or a buffer scale parameter issent.

The systems and methods disclosed herein describe electronic devices forsignaling a buffer parameter. For example, the systems and methodsdisclosed herein describe signaling a sub-picture buffer parameter bysending one or more sub-picture buffer parameters, such as a sub-picturecoded picture buffer (CPB) parameter. In some configurations, thesystems and methods disclosed herein may describe sending one or moresub-picture buffer parameters to a Hypothetical Reference Decoder (HRD).For example, this may be done in addition to sending one or morecorresponding picture buffer parameters to a HRD.

In some configurations, the systems and methods disclosed herein maydefine new syntax elements and semantics to signal a buffer size and/ora buffer scale parameter. These parameters may be calculated using theleaky bucket model of operation of HRD at the sub-picture level.Bitstream conformance restrictions may also be defined based on thesub-picture buffer parameters.

The systems and methods disclosed herein (e.g., the HRD modification)may perform operations, such as testing or verifying bitstreamconformance based on the one or more sub-picture buffer parameters. Forinstance, the systems and methods disclosed herein describe modificationto HRD parameters to allow for CPB operation on a sub-picture level.Additionally, CPB operations on the picture level or access unit levelmay be simultaneously supported.

In some configurations, the systems and methods disclosed herein maydescribe a decoder conformance constraint for interpolated deliveryschedules. For example, the decoder conformance constraint may be basedon the sub-picture buffer parameters, which may be sent to the decoder.

The systems and methods disclosed herein (e.g., the HRD modification)may provide a benefit of reducing buffer size, such as the CPB, when theHRD is operating at the sub-picture level. This may result in reducinghardware costs. For example, a smaller buffer size requires less memory,which results in less hardware memory being required.

In addition, the systems and methods disclosed herein may provide abenefit that the HRD will not overflow or underflow. For example, oneway this may be accomplished is through the signaling of buffer sizeand/or buffer scale parameters for sub-picture based CPB operation andthrough checking the bitstream for conformance.

It should be noted that although the term “hypothetical” is used inreference to an HRD, the HRD may be physically implemented. For example,“HRD” may describe an implementation of an actual decoder. In someconfigurations, an HRD may be implemented in order to determine whethera bitstream conforms to High Efficiency Video Coding (HEVC)specifications. For instance, an HRD may determine whether Type Ibitstreams and Type II bitstreams conform to HEVC specifications. A TypeI bitstream may include only Video Coding Layer (VCL) Network AccessLayer (NAL) units and filler data NAL units. A Type II bitstream mayinclude additional other NAL units and syntax elements.

In some known configurations, such as in Benjamin Bros et al., “Highefficiency video coding (HEVC) text specification draft 8,”JCTVC-J1003_d7, Stockholm, July 2012 (hereinafter “HEVC Draft 8”), thesub-picture based HRD model and related syntax and semantics aredescribed. The systems and methods disclosed herein may describemodifications to the syntax and semantics presented in HEVC Draft 8.

Examples regarding the operation of a CPB in accordance with the systemsand methods disclosed herein are given as follows. The specificationsgiven as follows may apply independently to each set of CPB parametersthat is present and to both Type I and Type II conformance in accordancewith HEVC specifications.

The timing of bitstream arrival (e.g., one or more bitstream arrivaltimes) may be determined as follows. The HRD may be initialized at anyone of the buffering period Supplemental Enhancement Information (SEI)messages. Prior to initialization, the CPB may be empty. It should benoted that after initialization, the HRD may not be initialized again bysubsequent buffering period SEI messages. In some configurations, theoperation of the CPB may independently apply to each set of CPBparameters that is present and to both the Type I and Type IIconformance points.

Each access unit may be referred to as access unit n, where the number nidentifies the particular access unit. The access unit that isassociated with the buffering period SEI message that initializes theCPB may be referred to as access unit 0. All other access units may bereferred to as access unit n, with n being incremented by 1 for the nextaccess unit in decoding order.

Each decoding unit may be referred to as decoding unit m, where thenumber m identifies the particular decoding unit. The first decodingunit in decoding order in access unit 0 is referred to as decoding unit0. The value of m is incremented by 1 for each subsequent decoding unitin decoding order.

The variables InitCpbRemovalDelay[SchedSelIdx] andInitCpbRemovalDelayOffset[SchedSelIdx] may be set as follows. If eitherof the following conditions is true, InitCpbRemovalDelay[SchedSelIdx]and InitCpbRemovalDelayOffset[SchedSelIdx] are set to the values of thecorresponding initial_alt_cpb_removal_delay[SchedSelIdx] andinitial_alt_cpb_removal_delay_offset[SchedSelIdx], respectively, of theassociated buffering period SEI message, then access unit 0 may be a BLAaccess unit for which the coded picture has nal_unit_type equal toBLA_W_DLP or BLA_N_LP, and the value of rap_cpb_params_present_flag ofthe associated buffering period SEI message is equal to 1. Also, iftrue, SubPicCpbFlag may equal to 1. Otherwise,InitCpbRemovalDelay[SchedSelIdx] andInitCpbRemovalDelayOffset[SchedSelIdx] may be set to the values of thecorresponding initial_cpb_removal_delay[SchedSelIdx] andinitial_cpb_removal_delay_offset[SchedSelIdx], respectively, of theassociated buffering period SEI message.

The time at which the first bit of decoding unit m begins to enter theCPB is referred to as the initial arrival time t_(ai)(m). The initialarrival time of decoding units may be derived as follows. If thedecoding unit is decoding unit 0, t_(ai)(0)=0. Otherwise (the decodingunit is decoding unit m with m>0), if cbr_flag[SchedSelIdx] is equal to1, the initial arrival time for decoding unit m, may be equal to thefinal arrival time (derived below) of decoding unit m−1.

In other words, t_(ai)(m)=t_(af)(m−1). Otherwise (cbr_flag[SchedSelIdx]may be equal to 0), the initial arrival time for decoding unit m isderived by t_(ai)(m)=Max(t_(af)(m−1), t_(ai,earliest)(m)), wheret_(ai,earliest)(m) is derived as follows. If decoding unit m is not thefirst decoding unit of a subsequent buffering period, t_(ai,earliest)(m)is derived ast_(ai,earliest)(m)=t_(r,n)(m)−(InitCpbRemovalDelay[SchedSelIdx]+InitCpbRemovalDelayOffset[SchedSelIdx])÷90000with t_(r,n)(m) being the nominal removal time of decoding unit m fromthe CPB as specified in subclause C.2.2 of HEVC Draft 8. Otherwise(decoding unit m is the first decoding unit of a subsequent bufferingperiod), t_(ai,earliest)(m) is derived as t_(ai,earliest)(m)=t_(r,n)(m)(InitCpbRemovalDelay[SchedSelIdx]÷90000).

The final arrival time for decoding unit m may be derived byt_(af)(m)=t_(ai)(m)+b(m)÷BitRate[SchedSelIdx], where b(m) is the size inbits of decoding unit m, counting the bits of the VCL NAL units and thefiller data NAL units for the Type I conformance point or all bits ofthe Type II bitstream for the Type II conformance point, where the TypeI and Type II conformance points are as shown in Figure C-1 of HEVCDraft 8.

The values of SchedSelIdx, BitRate[SchedSelIdx], andCpbSize[SchedSelIdx] may be constrained as follows. If the content ofthe active sequence parameter sets for the access unit containingdecoding unit m and the previous access unit differ, the hypotheticalstream delivery scheduler (HSS) may select a value SchedSelIdx1 ofSchedSelIdx from among the values of SchedSelIdx provided in the activesequence parameter set for the access unit containing decoding unit mthat results in a BitRate[SchedSelIdx1] or CpbSize[SchedSelIdx1] for theaccess unit containing decoding unit m. The value ofBitRate[SchedSelIdx1] or CpbSize[SchedSelIdx1] may differ from the valueof BitRate[SchedSelIdx0] or CpbSize[SchedSelIdx0] for the valueSchedSelIdx0 of SchedSelIdx that was in use for the previous accessunit. Otherwise, the HSS may continue to operate with the previousvalues of SchedSelIdx, BitRate[SchedSelIdx] and CpbSize[SchedSelIdx].

When the HSS selects values of BitRate[SchedSelIdx] orCpbSize[SchedSelIdx] that differ from those of the previous access unit,the following may apply. First, the variable BitRate[SchedSelIdx] comesinto effect at time t_(ai)(m). Second, the variable CpbSize[SchedSelIdx]comes into effect as follows. If the new value of CpbSize[SchedSelIdx]is greater than the old CPB size, it comes into effect at timet_(ai)(m). Otherwise, the new value of CpbSize[SchedSelIdx] comes intoeffect at the CPB removal time of the last decoding unit of the accessunit containing decoding unit m.

When SubPicCpbFlag is equal to 1, the initial CPB arrival time of accessunit n t_(ai)(n) may be set to the initial CPB arrival time of the firstdecoding unit in access unit n, and the final CPB arrival time of accessunit n t_(af)(n) may be set to the final CPB arrival time of the lastdecoding unit in access unit n. It should be noted that whenSubPicCpbFlag is equal to 0, each decoding unit is an access unit, hencethe initial and final CPB arrival times of access unit n may be theinitial and final CPB arrival times of decoding unit n.

The access unit that is associated with a buffering period SupplementalEnhancement Information (SEI) message that initializes the CPB may bereferred to as access unit 0. All other access units may be referred toas access unit n, with n being incremented by 1 for the next access unitin decoding order.

As illustrated by the foregoing, the systems and methods disclosedherein provide syntax and semantics that modify HRD parameters andsub-layer HRD parameters. In some configurations, the systems andmethods disclosed herein may be applied to HEVC specifications. Forexample, Table 1 below provides an example of syntax modifications tothe HRD parameters. Modifications are shown in bold.

TABLE 1   hrd_parameters( commonInfPresentFlag, MaxNumSubLayersMinus1 ){  if( commonInfPresentFlag ) {   timing_info_present_flag   if(timing_info_present_flag ) {    num_units_in_tick    time_scale   }  nal_hrd_parameters_present_flag   vcl_hrd_parameters_present_flag  if( nal_hrd_parameters_present_flag | |  vcl_hrd_parameters_present_flag ){    sub_pic_cpb_params_present_flag   if( sub_pic_cpb_params_present_flag ) {     tick_divisor_minus2    du_cpb_removal_delay_length_minus1    }    bit_rate_scale   cpb_size_scale    if( sub_pic_cpb_params_present_flag ) {    du_cpb_size_scale    }    initial_cpb_removal_delay_length_minus1   cpb_removal_delay_length_minus1    dpb_output_delay_length_minus1   } }  for( i = 0; i <= MaxNumSubLayersMinus1; i++) {  fixed_pic_rate_flag[i]   if( fixed_pic_rate_flag[i] )   pic_duration_in_tc_minus1[i]   low_delay_hrd_flag[i]  cpb_cnt_minus1[i]   if( nal_hrd_parameters_present_flag )   sub_layer_hrd_parameters( i )   if( vcl_hrd_parameters_present_flag )   sub_layer_hrd_parameters( i )  } }

Examples regarding HRD parameters semantics shown in Table 1, inaccordance with the systems and methods disclosed herein, are given asfollows. timing_info_present_flag equal to 1 may specify thatnum_units_in_tick and time_scale are present in the hrd_parameters( )syntax structure. timing_info_present_flag equal to 0 may specify thatnum_units_in_tick and time_scale are not present in the hrd_parameters() syntax structure.

num_units_in_tick may be the number of time units of a clock operatingat the frequency time_scale Hz that corresponds to one increment (calleda clock tick) of a clock tick counter. num_units_in_tick is generallygreater than 0. A clock tick may be the minimum interval of time thatcan be represented in the coded data whensub_pic_cpb_params_present_flag is equal to 0. For example, when thepicture rate of a video signal is 25 Hz, time_scale may be equal to27,000,000 and num_units_in_tick may be equal to 1,080,000.

time_scale may be the number of time units that pass in one second. Forexample, a time coordinate system that measures time using a 27 MHzclock has a time_scale of 27,000,000. time_scale is generally greaterthan 0.

nal_hrd_parameters present_flag equal to 1 may specify that NAL HRDparameters (pertaining to Type II bitstream conformance) are present inthe hrd_parameters( ) syntax structure. nal_hrd_parameters_present_flagequal to 0 specifies that NAL HRD parameters are not present in thehrd_parameters( ) syntax structure. It should be noted that whennal_hrd_parameters_present_flag is equal to 0, the conformance of thebitstream cannot be verified without provision of the NAL HRD parametersand all buffering period and picture timing SEI messages.

The variable NalHrdBpPresentFlag may be derived as follows. If one ormore of the following conditions are true, the value ofNalHrdBpPresentFlag is set equal to 1. In this case,nal_hrd_parameters_present_flag may be present in the bitstream and maybe equal to 1. Also, in this case, the need for presence of bufferingperiods for NAL HRD operation to be present in the bitstream inbuffering period SEI messages may be determined by the application.Otherwise, the value of NalHrdBpPresentFlag may be set equal to 0.

vcl_hrd_parameters_present_flag equal to 1 may specify that VCL HRDparameters (pertaining to all bitstream conformance) are present in thehrd_parameters( ) syntax structure. vcl_hrd_parameters_present_flagequal to 0 may specify that VCL HRD parameters are not present in thehrd_parameters( ) syntax structure. It should be noted that whenvcl_hrd_parameters_present_flag is equal to 0, the conformance of thebitstream cannot be verified without provision of the VCL HRD parametersand all buffering period and picture timing SEI messages.

The variable VclHrdBpPresentFlag is derived as follows. If one or moreof the following conditions are true, the value of VclHrdBpPresentFlagmay be set equal to 1. First, vcl_hrd_parameters_present_flag is presentin the bitstream and is equal to 1. Second, the need for presence ofbuffering periods for VCL HRD operation to be present in the bitstreamin buffering period SEI messages is determined by the application.Otherwise, the value of VclHrdBpPresentFlag may be set equal to 0.

The variable CpbDpbDelaysPresentFlag is derived as follows. If one ormore of the following conditions are true, the value ofCpbDpbDelaysPresentFlag may be set equal to 1. First,nal_hrd_parameters_present_flag is present in the bitstream and is equalto 1. Second, vcl_hrd_parameters_present flag is present in thebitstream and is equal to 1. Third, the need for presence of CPB and DPBoutput delays to be present in the bitstream in picture timing SEImessages is determined by the application. Otherwise, the value ofCpbDpbDelaysPresentFlag may be set equal to 0.

sub_pic_cpb_params_present_flag equal to 1 may specify that sub-picturelevel CPB removal delay parameters are present and the CPB may operateat access unit level or sub-picture level.sub_pic_cpb_params_present_flag equal to 0 may specify that sub-picturelevel CPB removal delay parameters are not present and the CPB operatesat access unit level. When sub_pic_cpb_params_present_flag is notpresent, its value may be inferred to be equal to 0.

tick_divisor_minus2 may specify the sub-picture clock tick. Asub-picture clock tick may be the minimum interval of time that can berepresented in the coded data when sub_pic_cpb_params_present_flag isequal to 1.

du_cpb_removal_delay_length_minus1 plus 1 may specify the length, inbits, of the du_cpb_removal_delay_minus1[i] andcommon_du_cpb_removal_delay_minus1 syntax elements of the picture timingSEI message. bit_rate_scale, together withbit_rate_value_minus1[SchedSelIdx], may specify the maximum input bitrate of the SchedSelIdx-th CPB.

cpb_size_scale, together with cpb_size_value_minus1[SchedSelIdx], mayspecify the CPB size of the SchedSelIdx-th CPB when operating at accessunit level. du_cpb_size_scale, together with du_cpb_size_value_minus1[SchedSelIdx], may specify the CPB size of the SchedSelIdx-th CPB whenoperating at sub-picture level.

initial_cpb_removal_delay_length_minus1 plus 1 may specify the length,in bits, of the initial_cpb_removal_delay[SchedSelIdx] andinitial_cpb_removal_delay_offset[SchedSelIdx] syntax elements of thebuffering period SEI message. When theinitial_cpb_removal_delay_length_minus1 syntax element is not present,it may be inferred to be equal to 23.

cpb_removal_delay_length_minus1 plus 1 may specify the length, in bits,of the cpb_removal_delay syntax element in the picture timing SEImessage. When the cpb_removal_delay_length_minus1 syntax element is notpresent, it may be inferred to be equal to 23.

dpb_output_delay_length_minus1 plus 1 may specify the length, in bits,of the dpb_output_delay syntax element in the picture timing SEImessage. When the dpb_output_delay_length_minus1 syntax element is notpresent, it may be inferred to be equal to 23.

fixed_pic_rate_flag[i] equal to 1 may indicate that, when HighestTid isequal to i, the temporal distance between the HRD output times of anytwo consecutive pictures in output order is constrained as follows.fixed_pic_rate_flag[i] equal to 0 indicates that no such constraintsapply to the temporal distance between the HRD output times of any twoconsecutive pictures in output order. When fixed_pic_rate_flag[i] is notpresent, it may be inferred to be equal to 0.

When HighestTid is equal to i and fixed_pic_rate_flag[i] is equal to 1for a coded video sequence containing picture n, the value computed forΔto,dpb(n), as specified in Equation C-17 of HEVC Draft 8, may be equalto tc*(pic_duration_in_tcs_minus1[i]+1), wherein tc is as specified inEquation C-1 of HEVC Draft 8 (using the value of tc for the coded videosequence containing picture n) when one or more of the followingconditions are true for the following picture nn that is specified foruse in Equation C-17. First, picture nn is in the same coded videosequence as picture n. Second, picture nn is in a different coded videosequence and fixed_pic_rate_flag[i] is equal to 1 in the coded videosequence containing picture nn, the value ofnum_units_in_tick÷time_scale is the same for both coded video sequences,and the value of pic_duration_in_tc_minus1[i] is the same for both codedvideo sequences.

pic_duration_in_tc_minus1[i] plus 1 may specify, when HighestTid isequal to i, the temporal distance, in clock ticks, between the HRDoutput times of any two consecutive pictures in output order in thecoded video sequence. The value of pic_duration_in_tc_minus1[i] mayrange from 0 to 2047, inclusive.

low_delay_hrd_flag[i] may specify the HRD operational mode, whenHighestTid is equal to i, as specified in Annex C of HEVC Draft 8. Whenfixed_pic_rate_flag[i] is equal to 1, low_delay_hrd_flag[i] may be equalto 0. It should be noted that when low_delay_hrd_flag[i] is equal to 1,“big pictures” that violate the nominal CPB removal times due to thenumber of bits used by an access unit may be permitted. It is expected,but not required, that such “big pictures” occur only occasionally.

cpb_cnt_minus1[i] plus 1 may specify the number of alternative CPBspecifications in the bitstream of the coded video sequence whenHighestTid is equal to i. The value of cpb_cnt_minus1[i] may range from0 to 31, inclusive. When low_delay_hrd_flag[i] is equal to 1,cpb_cnt_minus1[i] may be equal to 0. When cpb_cnt_minus1 [i] is notpresent, it may be inferred to be equal to 0.

As another example, Table 2 below provides alternative syntax HRDparameters. Modifications are shown in bold.

TABLE 2   hrd_parameters( commonInfPresentFlag, MaxNumSubLayersMinus1 ){  if( commonInfPresentFlag ) {   timing_info_present_flag   if(timing_info_present flag ) {    num_units_in_tick    time_scale   }  nal_hrd_parameters_present_flag   vcl_hrd_parameters_present_flag  if( nal_hrd_parameters_present_flag | |  vcl_hrd_parameters_present_flag ){    sub_pic_cpb_params_present_flag   if( sub_pic_cpb_params_present_flag ) {     tick_divisor_minus2    du_cpb_removal_delay_length_minus1     du_cpb_size_scale    }   bit_rate_scale    cpb_size_scale    ...  } }

Table 2 shows that, in some configurations, the syntax elements may besignaled at different positions. Additionally, in some configurations,the syntax element du_cpb_size_scale may be coded as u(4), which mayindicate the number of bits employed. A different number of bits thanthat indicated by u(4) may be used. For example, du_cpb_size_scale maybe coded as ue(v) or using some other coding technique.

Table 3 below provides syntax modifications to sub-layer HRD parameters.Modifications are shown in bold.

TABLE 3   sub_layer_hrd_parameters( tId ) {  for( SchedSelIdx = 0;SchedSelIdx <= cpb_cnt_minus1 [i];   SchedSelIdx++) {  bit_rate_value_minus1[SchedSelIdx]  cpb_size_value_minus1[SchedSelIdx]    if(sub_pic_cpb_params_present_flag ) {    du_cpb_size_value_minus1[SchedSelIdx]    }   cbr_flag[SchedSelIdx] } }

Examples regarding sub-layer HRD parameters semantics are shown in Table3, in accordance with the systems and methods disclosed herein, aregiven as follows. bit_rate_value_minus1[SchedSelIdx], together withbit_rate_scale, may specify the maximum input bit rate for theSchedSelIdx th CPB. bit_rate_value_minus1[SchedSelIdx] may range from 0to 232-2, inclusive. For any SchedSelIdx>0,bit_rate_value_minus1[SchedSelIdx] may be greater thanbit_rate_value_minus1[SchedSelIdx−1]. The bit rate in bits per second isgiven by

BitRate[SchedSelIdx]=(bit_rate_value_minus1[SchedSelIdx]+1)*2^((6+bit)^(—) ^(rate) ^(—) ^(scale)).

When the bit rate_value_minus1 [SchedSelIdx] syntax element is notpresent, the value of BitRate[SchedSelIdx] may be inferred to be equalto cpbBrVclFactor*MaxBR for VCL HRD parameters and may be inferred to beequal to cpbBrNalFactor*MaxBR for NAL HRD parameters, where MaxBR,cpbBrVclFactor and cpbBrNalFactor are specified in subclause A.4 of HEVCDraft 8.

cpb_size_value_minus1[SchedSelIdx] may be used together withcpb_size_scale to specify the SchedSelIdx-th CPB size.cpb_size_value_minus1[SchedSelIdx] may range from 0 to 232-2, inclusive.For any SchedSelIdx greater than 0, cpb_size_value_minus1[SchedSelIdx]may be less than or equal to cpb_size_value_minus1[SchedSelIdx−1].

When SubPicCpbFlag is equal to 0, the CPB size in bits is given byCpbSize[SchedSelIdx]=(cpb_size_value_minus1[SchedSelIdx]+1)*2^((4+cpb)^(—) ^(size) ^(—) ^(scale)).

When the cpb_size_value_minus1[SchedSelIdx] syntax element is notpresent, the value of CpbSize[SchedSelIdx] may be inferred to be equalto cpbBrVclFactor*MaxCPB for VCL HRD parameters and may be inferred tobe equal to cpbBrNalFactor*MaxCPB for NAL HRD parameters, where MaxCPB,cpbBrVclFactor and cpbBrNalFactor are specified in subclause A.4 of HEVCDraft 8.

du_cpb_size_value_minus1[SchedSelIdx] may be used together withdu_cpb_size_scale to specify the SchedSelIdx-th CPB size when operatingat sub-picture level. du_cpb_size_value_minus1[SchedSelIdx] may rangefrom 0 to 2³²−2, inclusive. For any SchedSelIdx greater than 0,du_cpb_size_value_minus1[SchedSelIdx] may be less than or equal todu_cpb_size_value_minus1[SchedSelIdx−1].

When SubPicCpbFlag is equal to 1, the CPB size in bits is given by

CpbSize[SchedSelIdx]=(du_cpb_size_value_minus1[SchedSelIdx]+1)*2^((4+du)^(—) ^(cpb) ^(—) ^(size) ^(—) ^(scale)).

When the du_cpb_size_value_minus1[SchedSelIdx] syntax element is notpresent, the value of CpbSize[SchedSelIdx] may be inferred to be equalto cpbBrVclFactor*MaxCPB for VCL HRD parameters and may be inferred tobe equal to cpbBrNalFactor*MaxCPB for NAL HRD parameters, where MaxCPB,cpbBrVclFactor and cpbBrNalFactor are specified in subclause A.4 of HEVCDraft 8.

cbr_flag[SchedSelIdx] equal to 0 may specify that to decode thisbitstream by the HRD using the SchedSelIdx-th CPB specification, thehypothetical stream delivery scheduler (HSS) operates in an intermittentbit rate mode. cbr_flag[SchedSelIdx] equal to 1 may specify that the HSSoperates in a constant bit rate (CBR) mode. When thecbr_flag[SchedSelIdx] syntax element is not present, the value ofcbr_flag is inferred to be equal to 0.

For convenience, several definitions are given as follows, which may beapplied to the systems and methods disclosed herein. A decoding unit(DU) may be an access unit or a subset of an access unit. If asub-picture CPB flag is equal to 0, the decoding unit is an access unit.Otherwise, the decoding unit is a subset of the access unit, such as asub-picture access unit or an access unit operating on a sub-picturelevel. The decoding unit may consist of one or more VCL NAL units in anaccess unit and associated non-VCL NAL units.

A buffering period may be specified as a set of access units between twoinstances of the buffering period SEI message in decoding order.Supplemental Enhancement Information (SEI) may include information thatis not necessary to decode the samples of coded pictures from VCL NALunits. SEI messages may assist in procedures related to decoding,display or other purposes. However, SEI messages may not be required forconstructing luma or chroma samples by a decoding process. Conformingdecoders may not be required to process this information for outputorder conformance to HEVC specifications (Annex C of HEVC Draft 8includes specifications for conformance, for example). Some SEI messageinformation may be required to check bitstream conformance and foroutput timing decoder conformance.

A buffering period SEI message may be an SEI message related tobuffering period. It may define syntax and semantics that definebitstream arrival timing and coded picture removal timing.

A Picture Parameter Set (PPS) is a syntax structure containing syntaxelements that apply to zero or more entire coded pictures as determinedby the pic_parameter_set_id syntax element found in each slice header.pic_parameter_set_id may identify the picture parameter set that isreferred to in the slice header. The value of pic_parameter_set_id maybe in the range of 0 to 255, inclusive.

A Coded Picture Buffer (CPB) may be a first-in first-out buffercontaining access units in decoding order specified in a hypotheticalreference decoder (HRD). An access unit may be a set of Network AccessLayer (NAL) units that are consecutive in decoding order and includeexactly one coded picture. In addition to the coded slice NAL units ofthe coded picture, the access unit may also include other NAL units notcontaining slices of the coded picture. The decoding of an access unitalways results in a decoded picture. A NAL unit may be a syntaxstructure containing an indication of the type of data to follow andbytes containing that data in the form of a raw byte sequence payload(RBSP) interspersed as necessary with emulation prevention bytes.

Various configurations are now described with reference to the Figures,where like reference numbers may indicate functionally similar elements.The systems and methods as generally described and illustrated in theFigures herein could be arranged and designed in a wide variety ofdifferent configurations. Thus, the following more detailed descriptionof several configurations, as represented in the Figures, is notintended to limit scope, as claimed, but is merely representative of thesystems and methods.

FIG. 1 is a block diagram illustrating an example of one or moreelectronic devices 102 in which systems and methods for signaling asub-picture buffer parameter may be implemented. In this example,electronic device A 102 a and electronic device B 102 b are illustrated.However, it should be noted that one or more of the features andfunctionality described in relation to electronic device A 102 a andelectronic device B 102 b may be combined into a single electronicdevice in some configurations.

Electronic device A 102 a includes an encoder 104. The encoder 104includes a sub-picture buffer parameter generation module 108. Each ofthe elements included within electronic device A 102 a (e.g., theencoder 104 and the sub-picture buffer parameter generation module 108)may be implemented in hardware, software or a combination of both.

Electronic device A 102 a may obtain one or more input pictures 106. Insome configurations, the input picture(s) 106 may be captured onelectronic device A 102 a using an image sensor, may be retrieved frommemory and/or may be received from another electronic device.

The encoder 104 may encode the input picture(s) 106 to produce encodeddata. For example, the encoder 104 may encode a series of input pictures106 (e.g., video). In one configuration, the encoder 104 may be an HEVCencoder. The encoded data may be digital data (e.g., part of a bitstream114). The encoder 104 may generate overhead signaling based on the inputsignal.

The sub-picture buffer parameter generation module 108 may generate oneor more sub-picture buffer parameters. The electronic device 102 (e.g.,the encoder 104) may determine whether a picture is allowed to bedecoded on a sub-picture level. In some cases, this may be determinedbased on whether a picture is encoded on a sub-picture level. In someinstances, the electronic device may determine whether the picture isallowed to be decoded on a sub-picture level in addition to beingallowed to be decoded at a picture level. If the picture is allowed tobe decoded on a sub-picture level, then the sub-picture buffer parametergeneration module 108 may generate a buffer size parameter and/or abuffer scale parameter. For example, the buffer size parameter may be asub-picture CPB size value parameter, such as du_cpb_size_value_minus1.As another example, the buffer scale parameter may be a sub-picture CPBsize scale parameter, such as du_cpb_size_scale.

The sub-picture buffer parameter generation module 108 may perform oneor more of the procedures described in connection with FIG. 2, FIG. 3and FIG. 4 below. In some configurations, electronic device A 102 a maysend data, such as encoded picture information, to electronic device B102 b as part of the bitstream 114. In some configurations, electronicdevice A 102 a may send a message to electronic device B 102 b by aseparate transmission 110. For example, the separate transmission 110may not be part of the bitstream 114. For instance, a buffering periodSEI message or other message may be sent using some out-of-bandmechanism. It should be noted that, in some configurations, the messagemay include one or more of the features of the sub-picture CPB sizescale parameter and/or another type of message, such as a bufferingperiod SEI message.

The encoder 104 (and sub-picture buffer parameter generation module 108,for example) may produce a bitstream 114. The bitstream 114 may includeencoded picture data based on the input picture(s) 106. In someconfigurations, the bitstream 114 may also include overhead data, suchas a sub-picture CPB size scale parameter, a buffering period SEImessage or other message, slice header(s), PPS(s), etc. As additionalinput pictures 106 are encoded, the bitstream 114 may include one ormore encoded pictures. For instance, the bitstream 114 may include oneor more encoded pictures with corresponding overhead data.

The bitstream 114 may be provided to a decoder 112. In one example, thebitstream 114 may be transmitted to electronic device B 102 b using awired or wireless link. In some cases, this may be done over a network,such as the Internet or a Local Area Network (LAN). As illustrated inFIG. 1, the decoder 112 may be implemented on electronic device B 102 bseparately from the encoder 104 on electronic device A 102 a. However,it should be noted that the encoder 104 and decoder 112 may beimplemented on the same electronic device in some configurations. In animplementation where the encoder 104 and decoder 112 are implemented onthe same electronic device, for instance, the bitstream 114 may beprovided over a bus to the decoder 112 or stored in memory for retrievalby the decoder 112.

The decoder 112 may be implemented in hardware, software or acombination of both. In one configuration, the decoder 112 may be anHEVC decoder. The decoder 112 may receive (e.g., obtain) the bitstream114. The decoder 112 may generate one or more decoded pictures 118 basedon the bitstream 114. The decoded picture(s) 118 may be displayed,played back, stored in memory and/or transmitted to another device, etc.

The decoder 112 may receive data (e.g., encoded picture data). Thedecoder may also receive a buffer parameter. For example, the decoder112 may receive a sub-picture CPB size scale parameter such asdu_cpb_size_scale. It should be noted that the sub-picture level bufferparameters (e.g., du_cpb_size_scale anddu_cpb_size_value_minus1[SchedSelIdx]), are sent in addition to thecorresponding picture level parameters (e.g., cpb_size_scale andcpb_size_value_minus1[SchedSelIdx]). Also, the sub-picture level bufferparameters, in most instances, differ from corresponding parameters atthe picture level. Additionally, it should be noted that theseparameters are sent for multiple bit rate values with SchedSelIdxindicating the index for the multiple different bitrate values.

The decoder 112 may include a CPB 120. The CPB 120 may temporarily storeencoded pictures. For example, the CPB 120 may store encoded picturesuntil a removal time. In accordance with the systems and methodsdisclosed herein, the storing and retaining of encoded picture may bebased on, in part, by the decoder 112 based on a sub-picture CPB sizescale and sub-picture CPS size parameters.

The decoder 112 may perform an interpolated delivery schedule test forsub-picture level CPB operation based on the sub-picture level CPBparameter. In some configurations, the decoder 112 may operate atinterpolated delivery bit rate. For example, the decoder 112 may includea decoder under test (DUT) (not shown) and the DUT may use the bufferparameter, such as a sub-picture CPB parameter, to verify that bitstreamconstraints are being regulated and that pictures are being properlyencoded by the encoder 104. The decoder 112 may perform one or more ofthe procedures described in connection with FIG. 5 below.

The HRD described above may be one example of the decoder 112illustrated in FIG. 1. Thus, an electronic device 102 may operate inaccordance with the HRD and CPB described above, in some configurations.

It should be noted that one or more of the elements or parts thereofincluded in the electronic device(s) 102 may be implemented in hardware.For example, one or more of these elements or parts thereof may beimplemented as a chip, circuitry or hardware components, etc. It shouldalso be noted that one or more of the functions or methods describedherein may be implemented in and/or performed using hardware. Forexample, one or more of the methods described herein may be implementedin and/or realized using a chipset, an Application-Specific IntegratedCircuit (ASIC), a Large-Scale Integrated circuit (LSI) or integratedcircuit, etc.

FIG. 2 is a flow diagram illustrating one configuration of a method 200for sending a sub-picture buffer parameter. An electronic device 102(e.g., electronic device A 102 a) may determine 202 whether a picture isallowed to be decoded on a sub-picture level. In some instances, theelectronic device 102 may determine 202 whether the picture is allowedto be decoded on a sub-picture level in addition to being allowed to bedecoded at a picture level. For example, the encoder 104 may determineto encode the input picture 106 at a sub-picture level picture. Itshould be appreciated that sub-picture level decoding can be enabled byusing various tools defined in HEVC specification, such as, but notlimited to, tiles, slices, wavefronts, entropy slices, dependent slices,etc.

If the encoder 104 determines 202 that the picture is allowed to bedecoded on a sub-picture level, and in some instances, the picture isallowed to be decoded on a sub-picture level in addition to a picturelevel, the electronic device 102 may generate 204 a buffer sizeparameter and/or a buffer scale parameter. Otherwise, the electronicdevice 102 may determine 202 that the picture is not allowed to bedecoded on a sub-picture level.

Accordingly, the electronic device 102 may generate 204 a buffer sizeparameter and/or a buffer scale parameter if the picture is allowed tobe decoded on a sub-picture level. In some instances, the electronicdevice 102 may generate 204 a buffer size parameter and/or a bufferscale parameter if the picture is allowed to be decoded on a sub-picturelevel in addition to the picture level.

In some configurations, the electronic device 102 may generate 204 twobuffer size parameters and/or two buffer scale parameters. One of thetwo buffer size parameters may correspond to an operation at the picturelevel and the other buffer size parameters may correspond to anoperation as a sub-picture level. Similarly, one of the two buffer scaleparameters may correspond to an operation at the picture level and theother buffer scale parameters may correspond to an operation as asub-picture level.

The buffer may be a coded picture buffer (CPB). The buffer sizeparameter may be a sub-picture CPB size value parameter, such asdu_cpb_size_value_minus1 [SchedSelIdx], as illustrated in Table 3 above,where SchedSelIdx is an index variable. For example, the sub-picture CPBsize value parameter may be used together with a sub-picture size scaleparameter to specify the CPB size for each index value when operating atsub-picture level. Each index value may correspond to a differentbitrate value. By specifying the CPB size, overflows and underflows maybe prevented, while maintaining a constant output rate.

The buffer scale parameter may be a sub-picture CPB size scaleparameter, such as du_cpb_size_scale, as illustrated in Table 1 andTable 2 above. The sub-picture CPB size scale size parameter may specifythe CPB size for each index value when operating at sub-picture level.The sub-picture CPB size scale size parameter may be used together witha buffer size parameter, such as the sub-picture CPB size valueparameter.

In one configuration, the buffer scale parameter may additionally be asub-picture bit rate scale parameter, such as du_bit_rate_scale, whichis defined in Table 4. Table 4 below provides alternative syntax HRDparameters. Modifications to known syntax are shown in bold.

TABLE 4   hrd_parameters( commonInfPresentFlag, MaxNumSubLayersMinus1 ){  if( commonInfPresentFlag) {   timing_info_present_flag   if(timing_info_present_flag ) {    num_units_in_tick    time_scale   }  nal_hrd_parameters_present_flag   vcl_hrd_parameters_present_flag  if( nal_hrd_parameters_present_flag | |  vcl_hrd_parameters_present_flag ){    sub_pic_cpb_params_present_flag   if( sub_pic_cpb_params_present_flag ) {    tick_divisor_minus2   du_cpb_removal_delay_length_minus1   }   bit_rate_scale  du_bit_rate_scale   cpb_size_scale   ...  } }

Examples regarding HRD parameters semantics shown in Table 4, inaccordance with the systems and methods disclosed herein, are given asfollows. bit_rate_scale, together withbit_rate_value_minus1[SchedSelIdx], may specify the maximum input bitrate of the SchedSelIdx-th CPB when operating at access unit level.du_bit_rate_scale, together with bit_rate_value_minus1[SchedSelIdx], mayspecify the maximum input bit rate of the SchedSelIdx-th CPB whenoperating at sub-picture level. Other semantics may be employed asdescribed above in connection with Tables 1-3 above.

Table 5 below provides syntax modifications to sub-layer HRD parameters.Modifications to known syntax are shown in bold.

TABLE 5   sub_layer_hrdparameters( tId ) {  for( SchedSelIdx = 0;SchedSelIdx <= cpb_cnt_minus1[i] ;   SchedSelIdx++) {  bit_rate_value_minus1[SchedSelIdx]  cpb_size_value_minus1[SchedSelIdx]   cbr_flag[SchedSelIdx]   if(sub_pic_cpb_params_present_flag ) {   du_bit_rate_value_minus1[SchedSelIdx]   du_cpb_size_value_minus1[SchedSelIdx]    du_cbr_flag[SchedSelIdx]   } } }

Examples regarding sub-layer HRD parameters semantics shown in Table 5,in accordance with the systems and methods disclosed herein, are givenas follows. du_bit_rate_value_minus1[SchedSelIdx], together withdu_bit_rate_scale, may specify the maximum input bit rate for theSchedSelIdx-th CPB when operating at sub-picture level.du_bit_rate_value_minus1[SchedSelIdx] may range from 0 to 2³²−2,inclusive. For any SchedSelIdx>0, du_bit_rate_value_minus1[SchedSelIdx]may be greater than du_bit_rate_value_minus1[SchedSelIdx−1]. WhenSubPicCpbFlag is equal to 1, the bit rate in bits per second may begiven byBitRate[SchedSelIdx]=(du_bit_rate_value_minus1[SchedSelIdx]+1)*2^((6+du)^(—) ^(bit) ^(—) ^(rate) ^(—) ^(scale)).

When the du_bit_rate_value_minus1[SchedSelIdx] syntax element is notpresent, the value of BitRate[SchedSelIdx] may be inferred to be equalto cpbBrVclFactor*MaxBR for VCL HRD parameters and may be equal tocpbBrNalFactor*MaxBR for NAL HRD parameters, where MaxBR, cpbBrVclFactorand cpbBrNalFactor are specified in subclause A.4 of HEVC Draft 8.

du_cpb_size_value_minus1[SchedSelIdx] may be used together withdu_cpb_size_scale to specify the SchedSelIdx-th CPB size when operatingat sub-picture level. du_cpb_size_value_minus1[SchedSelIdx] may rangefrom 0 to 2³²−2, inclusive. For any SchedSelIdx greater than 0,du_cpb_size_value_minus1[SchedSelIdx] may be less than or equal todu_cpb_size_value_minus1[SchedSelIdx−1].

du_cbr_flag[SchedSelIdx] equal to 0 may specify that to decode thisbitstream by the HRD using the SchedSelIdx-th CPB specification whenoperating at sub-picture level, the hypothetical stream deliveryscheduler (HSS) may operate in an intermittent bit rate mode.du_cbr_flag[SchedSelIdx] equal to 1 may specify that the HSS operates ina constant bit rate (CBR) mode. When the du_cbr_flag[SchedSelIdx] syntaxelement is not present, the value of du_cbr_flag may be inferred to beequal to 0. Other semantics may be employed as described above inconnection with Tables 1-4 above.

In some configurations, such as those shown in Table 4 and Table 5,separate values of bit rate scale, bit rate and/or CBR flag parametersmay be signaled for sub-picture level operation points compared to thoseparameter values for access unit level operation points. In other words,the sub-picture level of CPB operation may have one set of bit ratescale, bit rate and/or CBR flag parameters, while the access unit levelof CPB operation may have another set of bit rate scale, bit rate and/orCBR flag parameters.

Returning the FIG. 2, the sub-picture bit rate scale parameter may beemployed in addition to, or in place of the sub-picture CPB size scaleparameter. The sub-picture bit rate scale parameter may bedu_bit_rate_scale. The sub-picture bit rate scale parameter may specifythe maximum input bit rate for each index value in the CPB whenoperating at sub-picture level. The sub-picture bit rate scale parametermay be employed by the electronic device 102 along with a bit rate valueparameter, such as bit_rate_value_minus1 [SchedSelIdx], whereSchedSelIdx indicates an index value.

The electronic device 102 may send 206 the buffer parameter (e.g., thebuffer size parameter and/or the buffer scale parameter). For example,the electronic device 102 may transmit the buffer parameter via one ormore of wireless transmission, wired transmission, device bus, network,etc. For instance, electronic device A 102 a may transmit the bufferparameter to electronic device B 102 b. The buffer parameter may be partof the bitstream 114, for example. In some configurations, electronicdevice A 102 a may send 206 the buffer parameter to electronic device B102 b in a separate transmission 110 (that is not part of the bitstream114). For instance, the buffer parameter may be sent using someout-of-band mechanism.

In the configuration where two buffer size parameters and/or two bufferscale parameters are generated, the electronic device 102 may send 206the two buffer size parameters and/or the two buffer scale parameters.

FIG. 3 is a flow diagram illustrating a more specific configuration of amethod 300 for sending a sub-picture buffer parameter. An electronicdevice 102 (e.g., electronic device A 102 a) may determine 302 whether apicture is allowed to be decoded on a sub-picture level. In someinstances, the electronic device 102 may determine 302 whether thepicture is allowed to be decoded on a sub-picture level in addition toon a picture level. This may be accomplished as described in connectionwith FIG. 2 above.

The electronic device 102 may generate 304 a CPB size parameter and/or aCPB scale parameter if the picture is allowed to be decoded on asub-picture level. In some instances, the electronic device 102 generate304 a CPB size parameter and/or a CPB scale parameter if the picture isallowed to be decoded on a sub-picture level in addition to the picturelevel. This may be accomplished as described in connection with FIG. 2above. The CPB size parameter may be a sub-picture CPB size parameterand the CPB scale parameter may be a sub-picture CPB scale parameter.

The electronic device 102 may send 306 the CPB size parameter and/or theCPB scale parameter for the sub-picture level. The CPB size parameterand/or the CPB scale parameter may be sent as part of the bitstream 114,for example. In some configurations, electronic device A 102 a may send306 the CPB size parameter and/or the CPB scale parameter for thesub-picture level to electronic device B 102 b in a separatetransmission 110 that is not part of the bitstream 114. For example, theCPB size parameter may be sent to electronic device B 102 b to be usedfor testing transmitted pictures at the DUT.

The electronic device 102 may generate 308 a sub-picture CPB presentparameter if it is determined 302 that the picture is allowed to bedecoded on a sub-picture level. In some instances, the electronic device102 may generate 308 a sub-picture CPB present parameter if it isdetermined 302 that the picture is allowed to be decoded on asub-picture level in addition to on a picture. For example, thesub-picture CPB present parameter may be a flag, such as a sub-pictureCPB present flag. The sub-picture CPB present flag may have a Booleanvalue indicating whether the electronic device 102 determined 302 toallow the picture (e.g., input picture 106) to be decoded on asub-picture level. For example, the sub-picture CPB present flag may beset to positive (e.g., the sub-picture CPB present flag=1) when theelectronic device 102 determined 302 to allow the picture to be decodedon a sub-picture level, and in some instances, on a picture level aswell. The sub-picture CPB present flag may besub_pic_cpb_params_present_flag, as described above in connection withTables 1-5 above.

In some configurations, the sub-picture CPB present flag may be employedto determine if an operation should be executed. For example, the HRDmay verify that the sub-picture CPB present flag is set to positivebefore obtaining and/or processing additional parameters for thesub-picture level or before executing commands on the sub-picture level.As another example, the HRD may verify that the sub-picture CPB presentflag is set to positive before performing bitsream conformance tests onencoded sub-picture level pictures.

The electronic device 102 may send 310 the sub-picture CPB presentparameter. For example, the electronic device 102 may transmit thesub-picture CPB parameter via one or more of wireless transmission,wired transmission, device bus, network, etc. For instance, electronicdevice A 102 a may transmit the sub-picture CPB present parameter toelectronic device B 102 b. The sub-picture CPB present parameter may bepart of the bitstream 114, for example. In some configurations,electronic device A 102 a may send 310 the sub-picture CPB presentparameter to electronic device B 102 b in a separate transmission 110that is not part of the bitstream 114. For example, the sub-picture CPBpresent parameter may be sent to electronic device B 102 b to be usedfor testing transmitted encoded pictures at the DUT and/or for operationat sub-picture level.

The electronic device 102 may perform 312 a bitstream conformance teston the sub-picture level, if the picture is allowed to be decoded on asub-picture level. In some configurations, the electronic device 102 mayperform 312 a bitstream conformance test on the sub-picture level, ifthe picture is allowed to be decoded on both a sub-picture level and apicture level. The bitstream conformance test may be performed by theHRD on the encoder 104, for example. By performing a bitstreamconformance test, the encoder 104 may verify that buffer overflow orbuffer underflow will not occur at the CPB 120 at the decoder 112.

Bitstream conformance tests may be performed at the access unit leveland/or the sub-picture level. In some configurations, a sub-picture CPBparameter is present, such as the sub-picture CPB present flag, mayindicate if bitstream conformance tests should be performed at theaccess unit level or the sub-picture level. For example, the sub-pictureCPB parameter may be set to positive and may indicate that one or morebitstream conformance tests should be performed at the the sub-picturelevel. Bitstream conformance tests may test that the bit rate and CPBsize combinations specified by the HRD parameters (e.g., Tables 1, 2 and4) conform to the specified restrictions.

A bitstream of coded data conforming to HEVC Draft 8 may fulfil thefollowing requirements. It may be a requirement of bitstream conformancethat the first coded picture in a bitstream shall be a random accesspoint (RAP) picture (i.e. an IDR picture or a CRA picture or a BLApicture). The bitstream may be tested by the HRD for conformance asfollows. For Type I bitstreams, the number of tests carried out may beequal to cpb_cnt_minus1+1, where cpb_cnt_minus1 is either the syntaxelement of hrd_parameters( ) following thevcl_hrd_parameters_present_flag. One test may be carried out for accessunit level CPB operation for each bit rate and CPB size combinationspecified by hrd_parameters( ) following thevcl_hrd_parameters_present_flag. An additional test may be performed forsub-picture level CPB operation for each bit rate and CPB sizecombination specified by hrd_parameters( ) following thevcl_hrd_parameters_present_flag if sub_pic_cpb_params_present_flag isequal to 1. Each of these tests may be conducted at the Type Iconformance point shown in Figure C-1 of HEVC Draft 8.

For Type II bitstreams there can be two sets of tests. The number oftests of the first set may be equal to cpb_cnt_minus1+1, wherecpb_cnt_minus1 is either the syntax element of hrd_parameters( )following the vcl_hrd_parameters_present_flag or is determined by theapplication by other means not specified in this Specification. One testmay be carried out for access unit level CPB operation for each bit rateand CPB size combination. An additional test may be performed forsub-picture level CPB operation for each bit rate and CPB sizecombination specified by hrd_parameters( ) following thevcl_hrd_parameters_present_flag if sub_pic_cpb_params_present_flag isequal to 1. Each of these tests may be conducted at the Type Iconformance point shown in Figure C-1 of HEVC Draft 8. For these tests,only VCL and filler data NAL units may be counted for the input bit rateand CPB storage.

The number of tests of the second set, for Type II bitstreams, may beequal to cpb_cnt_minus1+1, where cpb_cnt_minus1 is either the syntaxelement of hrd_parameters( ) following thenal_hrd_parameters_present_flag or is determined by the application byother means not specified in this Specification. One test may be carriedout for access unit level CPB operation for each bit rate and CPB sizecombination specified by hrd_parameters( ) following thenal_hrd_parameters present_flag. An additional test may be performed forsub-picture level CPB operation for each bit rate and CPB sizecombination specified by hrd_parameters( ) following thevcl_hrd_parameters_present_flag if sub_pic_cpb_params_present_flag isequal to 1. Each of these tests may be conducted at the Type IIconformance point shown in Figure C-1 of HEVC Draft 8. For these tests,all NAL units (of a Type II NAL unit stream) or all bytes (of a bytestream) may be counted for the input bit rate and CPB storage. It shouldbe noted that NAL HRD parameters established by a value of SchedSelIdxfor the Type II conformance point shown in Figure C-1 of HEVC Draft 8may be sufficient to also establish VCL HRD conformance for the Type Iconformance point shown in Figure C-1 of HEVC Draft 8 for the samevalues of InitCpbRemovalDelay[SchedSelIdx], BitRate[ SchedSelIdx], andCpbSize[SchedSelIdx] for the VBR case (cbr_flag[SchedSelIdx] equal to0). This is because the data flow into the Type I conformance point maybe a subset of the data flow into the Type II conformance point andbecause, for the VBR case, the CPB may be allowed to become empty andstay empty until the time a next picture is scheduled to begin toarrive. For example, when decoding a coded video sequence conforming toone or more of the profiles specified in Annex A of HEVC Draft 8 usingthe decoding process specified in clauses 2-9 of HEVC Draft 8, when NALHRD parameters are provided for the Type II conformance point that notonly fall within the bounds set for NAL HRD parameters for profileconformance in item c of subclause A.4.2 of HEVC Draft 8 but also fallwithin the bounds set for VCL HRD parameters for profile conformance initem b) of subclause A.4.2 of HEVC Draft 8, conformance of the VCL HRDfor the Type I conformance point is also assured to fall within thebounds of item b) of subclause A.4.2 of HEVC Draft 8.

For each current picture that is decoded, the variables maxPicOrderCntand minPicOrderCnt may be set equal to the maximum and the minimum,respectively, of the PicOrderCntVal values of the current picture, theprevious picture in decoding order that has TemporalId equal to 0, theshort-term reference pictures in the reference picture set of thecurrent picture and all pictures n that have PicOutputFlag equal to 1and t_(r)(n)<t_(r)(currPic) and t_(o,dpb)(n)>=t_(r)(currPic), wherecurrPic is the current picture.

It may be a requirement of bitstream conformance that all of thefollowing 11 conditions shall be fulfilled for each of the tests. First,for each access unit n, with n>0, associated with a buffering period SEImessage, with Δt_(g,90)(n) specified byΔt_(g,90)(n)=90000*(t_(r,n)(n)−t_(af)(n−1)), the value ofInitCpbRemovalDelay[SchedSelIdx] shall be constrained as follows. Ifcbr_flag[SchedSelIdx] may be equal to 0,InitCpbRemovalDelay[SchedSelIdx]<=Ceil(Δt_(g,90)(n)). Otherwise(cbr_flag[SchedSelIdx] may be equal to 1),Floor(Δt_(g,90)(n))<=InitCpbRemovalDelay[SchedSelIdx]<=Ceil(Δt_(g,90)(n)).It should be noted that the exact number of bits in the CPB at theremoval time of each picture may depend on which buffering period SEImessage is selected to initialize the HRD. Encoders must take this intoaccount to ensure that all specified constraints must be obeyedregardless of which buffering period SEI message is selected toinitialize the HRD, as the HRD may be initialized at any one of thebuffering period SEI messages.

Second, a CPB overflow is specified as the condition in which the totalnumber of bits in the CPB is larger than the CPB size. The CPB shallnever overflow. Third, a CPB underflow is specified as the condition inwhich the nominal CPB removal time of decoding unit m t_(r,n)(m) is lessthan the final CPB arrival time of decoding unit m t_(af)(m) for anyvalue of m. When low_delay_hrd_flag is equal to 0, the CPB shall neverunderflow.

Fourth, when low_delay_hrd_flag is equal to 1, a CPB underflow may occurat decoding unit m. In this case, the final CPB arrival time of accessunit n containing decoding unit m t_(af)(n) shall be later than thenominal CPB removal time of access unit n containing decoding unit mt_(r,n)(n). Fifth, the nominal removal times of pictures from the CPB(starting from the second picture in decoding order), shall satisfy theconstraints on t_(r,n)(n) and t_(r)(n) expressed in subclauses A.4.1through A.4.2 of HEVC Draft 8.

Sixth, after the decoding process for a reference picture set asspecified in subclause 8.3.2 of HEVC Draft 8 has been invoked, thenumber of decoded pictures in the DPB, including all pictures marked as“used for reference” and all pictures n that have PicOutputFlag equal to1 and t_(r)(n)<t_(r)(currPic) and t_(o,dpb)(n)>=t_(r)(currPic), wherecurrPic is the current picture, but not including the current picture,with TemporalId lower than or equal to the TemporalId of the currentpicture, shall be less than or equal to Min(0,sps_max_dec_pic_buffering[TemporalId]−1). Seventh, all referencepictures shall be present in the DPB when needed for prediction. Eachpicture shall be present in the DPB at its DPB output time unless it isremoved from the DPB before its output time by one of the processesspecified in subclause C.3 of HEVC Draft 8.

Eighth, the value of maxPicOrderCnt−minPicOrderCnt shall be less thanMaxPicOrderCntLsb/2. Ninth, the value of Δ_(to,dpb)(n) as given byEquation C-17 of HEVC Draft 8, which is the difference between theoutput time of a picture and that of the first picture following it inoutput order and having pic_output_flag equal to 1, shall satisfy theconstraint expressed in subclause A.4.1 of HEVC Draft 8 for the profile,tier and level specified in the bitstream using the decoding processspecified in clauses 2-9 of HEVC Draft 8. Tenth, whensub_pic_cpb_params_present_flag is 1, the following relationship shallapply: cpb_removal_delay*t_(c)==t_(c) _(—)_(sub)*Σ(du_cpb_removal_minus1_(k)[i]+1) where i=0, . . . ,num_decoding_units_minus1.

Eleventh, the variable T_(du)(k) is derived as: T_(du)(k)=T_(du)(k−1)+t_(c) _(—) _(sub)*Σ (du_cpb_removal_minus1_(k)[i]+1), where i=0, .. . , num_decoding_units_minus1_(k), and wheredu_cpb_removal_delay_minus1_(k)[i] and num_decoding_units_minus1_(k) arethe corresponding parameters for i-th decoding unit of k'th access unit(with k=0 for the access unit that initialized the HRD and T_(du)(k)=0for k<1). When sub_pic_cpb_params_present_flag is 1, then(au_cpb_removal_delay_minus1+1)*t_(c)==T_(du)(k), whereau_cpb_removal_delay_minus1 corresponds to the k-th access unit, maybetrue.

FIG. 4 is a flow diagram illustrating another more specificconfiguration of a method 400 for sending a sub-picture bufferparameter. An electronic device 102 (e.g., electronic device A 102 a)may determine 402 whether a picture is allowed to be decoded on asub-picture level and, in some instances, whether the picture is allowedto be decoded on a picture level. This may be accomplished as describedin connection with FIGS. 2-3 above.

The electronic device 102 may generate 404 a CPB size parameter and/or aCPB scale parameter if the picture is allowed to be decoded on asub-picture level and, in some configurations, in addition to on apicture level. This may be accomplished as described in connection withFIG. 2 above. The CPB size parameter may be a sub-picture CPB sizeparameter and the CPB scale parameter may be a sub-picture CPB scaleparameter.

The electronic device 102 may send 406 the CPB size parameter and/or theCPB scale parameter for the sub-picture level. This may be accomplishedas described in connection with FIG. 2 above.

In one configuration, the electronic device 102 may generate 408 asub-picture rate parameter, such as a sub-picture rate value parameter,if it is determined that the picture is allowed to be decoded on asub-picture level and, in some instances, also on a picture level. Thesub-picture rate value parameter may specify the maximum input bit ratefor each index value when operating at sub-picture level. Thesub-picture rate value parameter may be used in conjunction with thesub-picture bit rate scale parameter, such as du_bit_rate_scale, tospecify the maximum bit rate. The sub-picture rate value parameter maybe du_bit_rate_value_minus1[SchedSelIdx], as described above inconnection with Table 5 above.

The electronic device 102 may send 410 the sub-picture bit rate valueparameter. This may be accomplished as described in connection withFIGS. 2-3 above. For example, in some configurations, the sub-picturebit rate scale parameter may be sent, in the bitstream 114 and/or in aseparate transmission 110, to electronic device B 102 b to assist indecoding encoded pictures at the decoder 112.

It should be noted that the sub-picture level buffer parameters (e.g.,du_cpb_size_scale and du_cpb_size_value_minus1[SchedSelIdx]), are sentin addition to the corresponding picture level parameters (e.g.,cpb_size_scale and cpb_size_value_minus1[SchedSelIdx]). Also, thesub-picture level buffer parameters, in most instances, differ fromcorresponding parameters at the picture level. Additionally, it shouldbe noted that these parameters are sent for multiple bit rate valueswith SchedSelIdx indicating the index for the multiple different bitratevalues.

In another configuration, the electronic device 102 may generate 412 asub-picture rate parameter, such as a sub-picture bit rate flag, if itis determined that the picture is allowed to be decoded on a sub-picturelevel and, in some instances, if it determined that the picture is alsoallowed to be decoded on a picture level. The HRD may generate and setthe sub-picture bit rate flag for each index value corresponding to theCPB at sub-picture level. If the sub-picture bit rate flag is notpresent, the sub-picture bit rate flag may be inferred to equal to zero.The sub-picture bit rate flag may be du_cbr_flag[SchedSelIdx], asdescribed above in connection with Table 5 above. The sub-picture bitrate flag may be set for each index value in the CPB.

The sub-picture bit rate flag may be generated in addition to thesub-picture rate value parameter. The sub-picture bit rate flag mayspecify if a hypothetical stream delivery scheduler (HSS) should operatein an intermittent bit rate mode or in constant bit rate (CBR) mode todecode a bitstream 114. For example, the sub-picture bit rate flag maybe set to zero to indicate to the HSS to operate in an intermittent bitrate mode to decode a bitstream 114. The sub-picture bit rate flag maybe set to one may indicate to the HSS to operate in CBR mode to decode abitstream 114.

The electronic device 102 may send 414 the sub-picture bit rate flag, ifit is determined that the picture is allowed to be decoded on asub-picture level and, in some instances, if it determined that thepicture is also allowed to be decoded on a picture level. This may beaccomplished as described in connection with FIGS. 2-3 above. Forexample, in some configurations, the sub-picture bit rate scaleparameter may be sent, in the bitstream 114 and/or in a separatetransmission 110, to electronic device B 102 b to assist in decodingencoded pictures at the decoder 112.

It should be noted that the sub-picture level buffer parameters (e.g.,du_cpb_size_scale and du_cpb_size_value_minus1 [SchedSelIdx]), are sentin addition to the corresponding picture level parameters (e.g.,cpb_size_scale and cpb_size_value_minus1[SchedSelIdx]). Also, thesub-picture level buffer parameters, in most instances, differ fromcorresponding parameters at the picture level. Additionally, it shouldbe noted that these parameters are sent for multiple bit rate valueswith SchedSelIdx indicating the index for the multiple different bitratevalues.

FIG. 5 is a flow diagram illustrating one configuration of a method 500for receiving a sub-picture buffer parameter. An electronic device 102(e.g., electronic device B 102 b) may receive 502 data. The data may beencoded picture data, messages such as a buffering period SEI messageand/or buffer parameters. For example, the electronic device 102 mayreceive 502 the data via one or more of wireless transmission, wiredtransmission, device bus, network, etc. For instance, electronic deviceB 102 b may receive 502 the data from electronic device A 102 a. Thedata may be part of the bitstream 114, for example. In another example,electronic device B 102 b may receive the data from electronic device A102 a in a separate transmission 110 (that is not part of the bitstream114, for example). For instance, one or more buffer parameters may bereceived using some out-of-band mechanism. In some configurations, themessage may include the sub-picture CPB size scale parameter.

The electronic device 102 may obtain 504 a sub-picture level codedpicture buffer (CPB) parameter, such as a CPB size parameter and/or aCPB scale parameter for the sub-picture level. For example, thesub-picture level CPB parameter may be obtained from the data receivedas part of the bitstream 114 and/or from data received in as part of aseparate transmission 110.

In some configurations, the electronic device 102 may perform 506 asub-picture level CPB operation based on the sub-picture level CPBparameter. In some configurations, the sub-picture level CPB parametermay include data useful to specify operation as per hypotheticalreference decoder (HRD). In this configuration, the decoder 112 mayoperate the CPB 120 as defined by the HRD operation. In other words, thedecoder 112 may use the signaled CPB size parameter and/or the CPB scaleparameter provided to operate the CPB 120 on the decoder 112 as peroperation specified for the HRD. Using the signaled CPB size parameterand/or the CPB scale parameter as per the HRD specification may help toensure that buffer overflow or buffer underflow will not occur at theCPB 120 at the decoder 112.

Additionally or alternatively, the electronic device 102 may perform asub-picture level CPB operation, such as an interpolated deliveryschedule test for sub-picture level CPB operation, based on thesub-picture level CPB parameter. The interpolated delivery schedule testfor sub-picture level CPB operation may be based on the sub-picturelevel CPB parameter. For example, the electronic device 102 may be adecoder 112 having a decoder under test (DUT). The DUT may perform 506one or more interpolated delivery schedule tests on a sub-picture levelfor the CPB 120 based on the sub-picture level CPB parameter. Thesub-picture level CPB parameter may be the sub-picture CPB size scaleparameter.

The interpolated delivery schedule test may be performed separately forthe access unit level CPB operation and for sub-picture level CPBoperation. A decoder conforming to HEVC Draft 8 may fulfil the followingrequirements. A decoder claiming conformance to a specific profile, tierand level may be able to successfully decode all bitstreams that conformto the bitstream conformance requirements specified in subclause C.4 ofHEVC Draft 8, in the manner specified in Annex A of HEVC Draft 8,provided that all sequence parameter sets and picture parameter setsreferred to in the VCL NAL units, and appropriate buffering period andpicture timing SEI messages are conveyed to the decoder, in a timelymanner, either in the bitstream (by non-VCL NAL units), or by externalmeans not specified by HEVC Draft 8.

When a bitstream contains syntax elements that have values that arespecified as reserved and it is specified that decoders shall ignore thevalues of the syntax elements or the NAL units containing the syntaxelements having the reserved values, and the bitstream is otherwiseconforming to HEVC Draft 8, a conforming decoder may decode thebitstream in the same manner as it would decode a conforming bitstreamand shall ignore the reserved values of the syntax elements or the NALunits containing the syntax elements as specified.

There may be two types of conformance that can be claimed by a decoder:output timing conformance and output order conformance. To checkconformance of a decoder, test bitstreams conforming to the claimedprofile, tier and level, as specified by subclause C.4 of HEVC Draft 8may be delivered by a hypothetical stream scheduler (HSS) both to theHRD and to the decoder under test (DUT). All pictures output by the HRDmay also be output by the DUT and, for each picture output by the HRD,the values of all samples that are output by the DUT for thecorresponding picture may be equal to the values of the samples outputby the HRD.

For output timing decoder conformance, the HSS operates as describedabove, with delivery schedules selected only from the subset of valuesof SchedSelIdx for which the bit rate and CPB size are restricted asspecified in Annex A of HEVC Draft 8 for the specified profile, tier andlevel, or with “interpolated” delivery schedules as specified below forwhich the bit rate and CPB size may be restricted as specified in AnnexA of HEVC Draft 8. The same delivery schedule may be used for both theHRD and DUT.

When the HRD parameters and the buffering period SEI messages arepresent with cpb_cnt_minus1 greater than 0, the decoder may be capableof decoding the bitstream as delivered from the HSS operating using an“interpolated” delivery schedule specified as having peak bit rate r,CPB size c(r), and initial CPB removal delay (f(r)÷r) as follows:

α=(r−BitRate[SchedSelIdx−1])÷(BitRate[SchedSelIdx]−BitRate[SchedSelIdx−1]),

c(r)=α*CpbSize[SchedSelIdx]+(1−α)*CpbSize[SchedSelIdx−1],

f(r)=α*InitCpbRemovalDelay[SchedSelIdx]*BitRate[SchedSelIdx]+(1−α)*InitCpbRemovalDelay[SchedSelIdx−1]*BitRate[SchedSelIdx−1]

for any SchedSelIdx>0 and r such thatBitRate[SchedSelIdx−1]<=r<=BitRate[SchedSelIdx] such that r and c(r) arewithin the limits as specified in Annex A for the maximum bit rate andbuffer size for the specified profile, tier and level.

The above interpolated delivery schedule test may be performedseparately for the access unit level CPB operation and for sub-picturelevel CPB operation. In the case of access unit level test, theCpbSize[SchedSelIdx] may be set as CpbSize[SchedSelIdx](cpb_sizevalue_minus1[SchedSelIdx]+1)*2(4+cpb_size_scale).

In the case of sub-picture level test, the CpbSize[SchedSelIdx] may beset asCpbSize[SchedSelIdx]=(du_cpb_size_value_minus1[SchedSelIdx]+1)*2^((4+du)^(—) ^(cpb) ^(—) ^(size) ^(—) ^(scale)). It should be noted thatInitCpbRemovalDelay[SchedSelIdx] can be different from one bufferingperiod to another and may have to be recalculated.

For output timing decoder conformance, an HRD as described above may beused and the timing (relative to the delivery time of the first bit) ofpicture output may be the same for both HRD and the DUT up to a fixeddelay.

For output order decoder conformance, the HSS may deliver the bitstreamto the DUT “by demand” from the DUT, meaning the HSS delivers bits (indecoding order) only when the DUT requires more bits to proceed with itsprocessing. It should be noted that this may mean that for this test,the coded picture buffer of the DUT could be as small as the size of thelargest access unit.

A modified HRD as described below may be used, and the HSS may deliverthe bitstream to the HRD by one of the schedules specified in thebitstream such that the bit rate and CPB size are restricted asspecified in Annex A of HEVC Draft 8. The order of pictures output maybe the same for both HRD and the DUT.

For output order decoder conformance, the HRD CPB size may be equal toCpbSize[SchedSelIdx] for the selected schedule and the DPB size may beequal to MaxDpbSize. Removal time from the CPB for the HRD may be equalto the final bit arrival time and decoding may be immediate.

The electronic device 102 may provide feedback (not shown) to theencoder 104 based on the results of the interpolated delivery scheduletest. For example, feedback may be sent via a feedback link. Forinstance, the separate transmission 110 may be able to send and receivevarious parameters, feedback and test results between the encoder 104and the decoder 112. In this manner, encoder 102 may operate such thatit does not violate the buffer size parameter and/or the buffer scaleparameter sent to the decoder 112.

FIG. 6 is a block diagram illustrating one configuration of an encoder604 on an electronic device 602. It should be noted that one or more ofthe elements illustrated as included within the electronic device 602may be implemented in hardware, software or a combination of both. Forexample, the electronic device 602 includes an encoder 604, which may beimplemented in hardware, software or a combination of both. Forinstance, the encoder 604 may be implemented as a circuit, integratedcircuit, application-specific integrated circuit (ASIC), processor inelectronic communication with memory with executable instructions,firmware, field-programmable gate array (FPGA), etc., or a combinationthereof. In some configurations, the encoder 604 may be an HEVC coder.

The electronic device 602 may include a source 622. The source 622 mayprovide picture or image data (e.g., video) as one or more inputpictures 606 to the encoder 604. Examples of the source 622 may includeimage sensors, memory, communication interfaces, network interfaces,wireless receivers, ports, etc.

One or more input pictures 606 may be provided to an intra frameprediction module and reconstruction buffer 624. An input picture 606may also be provided to a motion estimation and motion compensationmodule 646 and to a subtraction module 628.

The intra frame prediction module and reconstruction buffer 624 maygenerate intra mode information 640 and an intra signal 626 based on oneor more input pictures 606 and reconstructed data 660. The motionestimation and motion compensation module 646 may generate inter modeinformation 648 and an inter signal 644 based on one or more inputpictures 606 and a reference picture buffer 676 signal 678. In someconfigurations, the reference picture buffer 676 may include data fromone or more reference pictures in the reference picture buffer 676.

The encoder 604 may select between the intra signal 626 and the intersignal 644 in accordance with a mode. The intra signal 626 may be usedin order to exploit spatial characteristics within a picture in an intracoding mode. The inter signal 644 may be used in order to exploittemporal characteristics between pictures in an inter coding mode. Whilein the intra coding mode, the intra signal 626 may be provided to thesubtraction module 628 and the intra mode information 640 may beprovided to an entropy coding module 642. While in the inter codingmode, the inter signal 644 may be provided to the subtraction module 628and the inter mode information 648 may be provided to the entropy codingmodule 642.

Either the intra signal 626 or the inter signal 644 (depending on themode) is subtracted from an input picture 606 at the subtraction module628 in order to produce a prediction residual 630. The predictionresidual 630 is provided to a transformation module 632. Thetransformation module 632 may compress the prediction residual 630 toproduce a transformed signal 634 that is provided to a quantizationmodule 636. The quantization module 636 quantizes the transformed signal634 to produce transformed and quantized coefficients (TQCs) 638.

The TQCs 638 are provided to an entropy coding module 642 and an inversequantization module 650. The inverse quantization module 650 performsinverse quantization on the TQCs 638 to produce an inverse quantizedsignal 652 that is provided to an inverse transformation module 654. Theinverse transformation module 654 decompresses the inverse quantizedsignal 652 to produce a decompressed signal 656 that is provided to areconstruction module 658.

The reconstruction module 658 may produce reconstructed data 660 basedon the decompressed signal 656. For example, the reconstruction module658 may reconstruct (modified) pictures. The reconstructed data 660 maybe provided to a deblocking filter 662 and to the intra predictionmodule and reconstruction buffer 624. The deblocking filter 662 mayproduce a filtered signal 664 based on the reconstructed data 660.

The filtered signal 664 may be provided to a sample adaptive offset(SAO) module 666. The SAO module 666 may produce SAO information 668that is provided to the entropy coding module 642. In someconfigurations, an SAO signal 670 is optionally provided to an adaptiveloop filter (ALF) 672. In this configuration, the ALF 672 produces anALF signal 674 that is provided to the reference picture buffer 676.Also, in this configuration, the ALF signal 674 may include data fromone or more pictures that may be used as reference pictures.

The entropy coding module 642 may code the TQCs 638 to produce bitstreamA 614 a (e.g., encoded picture data). For example, the entropy codingmodule 642 may code the TQCs 638 using Context-Adaptive Variable LengthCoding (CAVLC) or Context-Adaptive Binary Arithmetic Coding (CABAC). Inparticular, the entropy coding module 642 may code the TQCs 638 based onone or more of intra mode information 640, inter mode information 648and SAO information 668. Bitstream A 614 a (e.g., encoded picture data)may be provided to a sub-picture buffer parameter generation module 608.The sub-picture buffer parameter generation module 608 may be configuredsimilarly to the sub-picture buffer parameter generation module 108described in connection with FIG. 1. Additionally, the sub-picturebuffer parameter generation module 608 may perform one or more of theprocedures described in connection with FIG. 2, FIG. 3 and/or FIG. 4.

For example, the sub-picture buffer parameter generation module 608 maygenerate a sub-picture buffer parameter, such as the sub-picture CPBsize scale parameter and/or a sub-picture size parameter. In someconfigurations, the sub-picture buffer parameter may be inserted intobitstream A 614 a to produce bitstream B 614 b. Thus, the message may begenerated after the entire bitstream A 614 a is generated (e.g., aftermost of bitstream B 614 b is generated), for example. In otherconfigurations, the sub-picture buffer parameter may not be insertedinto bitstream A 614 a (in which case bitstream B 614 b may be the sameas bitstream A 614 a), but may be provided in a separate transmission610.

In some configurations, the electronic device 602 sends the bitstream614 to another electronic device. For example, the bitstream 614 may beprovided to a communication interface, network interface, wirelesstransmitter, port, etc. For instance, the bitstream 614 may betransmitted to another electronic device via LAN, the Internet, acellular phone base station, etc. The bitstream 614 may additionally oralternatively be stored in memory or another component on the electronicdevice 602.

FIG. 7 is a block diagram illustrating one configuration of a decoder712 on an electronic device 702. The decoder 712 may be included in anelectronic device 702. For example, the decoder 712 may be an HEVCdecoder. The decoder 712 and one or more of the elements illustrated asincluded in the decoder 712 may be implemented in hardware, software ora combination of both. The decoder 712 may receive a bitstream 714(e.g., one or more encoded pictures and overhead data included in thebitstream 714) for decoding. It should be noted that one or more accessunits may be included in the bitstream 714 and may include one or moreof encoded picture data and overhead data.

In some configurations, the received bitstream 714 may include receivedoverhead data, such as a sub-picture buffer parameter, a message (e.g.,buffer period SEI message or other message), slice header, PPS, etc. Insome configurations, the decoder 712 may additionally receive a separatetransmission 710. The separate transmission 710 may include asub-picture buffer parameter (e.g., a sub-picture CPB size scaleparameter or other buffer parameter). For example, a sub-picture CPBsize scale parameter or other buffer parameter may be received in aseparate transmission 710 instead of in the bitstream 714. However, itshould be noted that the separate transmission 710 may be optional andmay not be utilized in some configurations.

The decoder 712 includes a CPB 720. The CPB 720 may be configuredsimilarly to the CPB 120 described in connection with FIG. 1 above.Additionally or alternatively, the decoder 712 may perform one or moreof the procedures described in connection with FIG. 5. For example, thedecoder 712 may receive a buffer parameter (e.g., a sub-picture CPB sizescale parameter or other buffer parameter). Additionally, the decoder712 may perform an interpolated delivery schedule test for sub-picturelevel CPB operation. The interpolated delivery schedule test may bebased on the sub-picture level CPB parameter. Additionally, the decoder712 may perform bitstream conformance tests for sub-picture level CPBoperation. Furthermore, the decoder 712 may operate the CPB accordingthe specification of hypothetical reference decoder operation specifiedin HEVC specification, such as defined in HEVC Draft 8.

The Coded Picture Buffer (CPB) 720 may provide encoded picture data toan entropy decoding module 701. The encoded picture data may be entropydecoded by an entropy decoding module 701, thereby producing a motioninformation signal 703 and quantized, scaled and/or transformedcoefficients 705.

The motion information signal 703 may be combined with a portion of areference frame signal 798 from a frame memory 709 at a motioncompensation module 780, which may produce an inter frame predictionsignal 782. The quantized, descaled and/or transformed coefficients 705may be inverse quantized, scaled and inverse transformed by an inversemodule 707, thereby producing a decoded residual signal 784. The decodedresidual signal 784 may be added to a prediction signal 792 to produce acombined signal 786. The prediction signal 792 may be a signal selectedfrom either the inter frame prediction signal 782 produced by the motioncompensation module 780 or an intra frame prediction signal 790 producedby an intra frame prediction module 788. In some configurations, thissignal selection may be based on (e.g., controlled by) the bitstream714.

The intra frame prediction signal 790 may be predicted from previouslydecoded information from the combined signal 786 (in the current frame,for example). The combined signal 786 may also be filtered by ade-blocking filter 794. The resulting filtered signal 796 may be writtento frame memory 709. The resulting filtered signal 796 may include adecoded picture. The frame memory 709 may provide a decoded picture 718.

FIG. 8 illustrates various components that may be utilized in atransmitting electronic device 802. One or more of the electronicdevices 102, 602, 702 described herein may be implemented in accordancewith the transmitting electronic device 802 illustrated in FIG. 8.

The transmitting electronic device 802 includes a processor 817 thatcontrols operation of the electronic device 802. The processor 817 mayalso be referred to as a central processing unit (CPU). Memory 811,which may include both read-only memory (ROM), random access memory(RAM) or any type of device that may store information, providesinstructions 813 a (e.g., executable instructions) and data 815 a to theprocessor 817. A portion of the memory 811 may also include non-volatilerandom access memory (NVRAM). The memory 811 may be in electroniccommunication with the processor 817.

Instructions 813 b and data 815 b may also reside in the processor 817.Instructions 813 b and/or data 815 b loaded into the processor 817 mayalso include instructions 813 a and/or data 815 a from memory 811 thatwere loaded for execution or processing by the processor 817. Theinstructions 813 b may be executed by the processor 817 to implement thesystems and methods disclosed herein. For example, the instructions 813b may be executable to perform one or more of the methods 200, 300, 400,500 described above.

The transmitting electronic device 802 may include one or morecommunication interfaces 819 for communicating with other electronicdevices (e.g., receiving electronic device). The communicationinterfaces 819 may be based on wired communication technology, wirelesscommunication technology, or both. Examples of a communication interface819 include a serial port, a parallel port, a Universal Serial Bus(USB), an Ethernet adapter, an IEEE 1394 bus interface, a small computersystem interface (SCSI) bus interface, an infrared (IR) communicationport, a Bluetooth wireless communication adapter, a wireless transceiverin accordance with 3rd Generation Partnership Project (3GPP)specifications and so forth.

The transmitting electronic device 802 may include one or more outputdevices 823 and one or more input devices 821. Examples of outputdevices 823 include a speaker, printer, etc. One type of output devicethat may be included in an electronic device 802 is a display device825. Display devices 825 used with configurations disclosed herein mayutilize any suitable image projection technology, such as a cathode raytube (CRT), liquid crystal display (LCD), light-emitting diode (LED),gas plasma, electroluminescence or the like. A display controller 827may be provided for converting data stored in the memory 811 into text,graphics, and/or moving images (as appropriate) shown on the display825. Examples of input devices 821 include a keyboard, mouse,microphone, remote control device, button, joystick, trackball,touchpad, touchscreen, lightpen, etc.

The various components of the transmitting electronic device 802 arecoupled together by a bus system 829, which may include a power bus, acontrol signal bus and a status signal bus, in addition to a data bus.However, for the sake of clarity, the various buses are illustrated inFIG. 8 as the bus system 829. The transmitting electronic device 802illustrated in FIG. 8 is a functional block diagram rather than alisting of specific components.

FIG. 9 is a block diagram illustrating various components that may beutilized in a receiving electronic device 902. One or more of theelectronic devices 102, 602, 702 described herein may be implemented inaccordance with the receiving electronic device 902 illustrated in FIG.9.

The receiving electronic device 902 includes a processor 917 thatcontrols operation of the electronic device 902. The processor 917 mayalso be referred to as a CPU. Memory 911, which may include bothread-only memory (ROM), random access memory (RAM) or any type of devicethat may store information, provides instructions 913 a (e.g.,executable instructions) and data 915 a to the processor 917. A portionof the memory 911 may also include non-volatile random access memory(NVRAM). The memory 911 may be in electronic communication with theprocessor 917.

Instructions 913 b and data 915 b may also reside in the processor 917.Instructions 913 b and/or data 915 b loaded into the processor 917 mayalso include instructions 913 a and/or data 915 a from memory 911 thatwere loaded for execution or processing by the processor 917. Theinstructions 913 b may be executed by the processor 917 to implement thesystems and methods disclosed herein. For example, the instructions 913b may be executable to perform one or more of the methods 200, 300, 400,500 described above.

The receiving electronic device 902 may include one or morecommunication interfaces 919 for communicating with other electronicdevices (e.g., a transmitting electronic device). The communicationinterface 919 may be based on wired communication technology, wirelesscommunication technology, or both. Examples of a communication interface919 include a serial port, a parallel port, a Universal Serial Bus(USB), an Ethernet adapter, an IEEE 1394 bus interface, a small computersystem interface (SCSI) bus interface, an infrared (IR) communicationport, a Bluetooth wireless communication adapter, a wireless transceiverin accordance with 3rd Generation Partnership Project (3GPP)specifications and so forth.

The receiving electronic device 902 may include one or more outputdevices 923 and one or more input devices 921. Examples of outputdevices 923 include a speaker, printer, etc. One type of output devicethat may be included in an electronic device 902 is a display device925. Display devices 925 used with configurations disclosed herein mayutilize any suitable image projection technology, such as a cathode raytube (CRT), liquid crystal display (LCD), light-emitting diode (LED),gas plasma, electroluminescence or the like. A display controller 927may be provided for converting data stored in the memory 911 into text,graphics, and/or moving images (as appropriate) shown on the display925. Examples of input devices 921 include a keyboard, mouse,microphone, remote control device, button, joystick, trackball,touchpad, touchscreen, lightpen, etc.

The various components of the receiving electronic device 902 arecoupled together by a bus system 929, which may include a power bus, acontrol signal bus and a status signal bus, in addition to a data bus.However, for the sake of clarity, the various buses are illustrated inFIG. 9 as the bus system 929. The receiving electronic device 902illustrated in FIG. 9 is a functional block diagram rather than alisting of specific components.

FIG. 10 is a block diagram illustrating one configuration of anelectronic device 1002 in which systems and methods for sending amessage may be implemented. The electronic device 1002 includes encodingmeans 1031 and transmitting means 1033. The encoding means 1031 andtransmitting means 1033 may be configured to perform one or more of thefunctions described in connection with one or more of FIG. 1, FIG. 2,FIG. 3, FIG. 4, FIG. 6 and FIG. 8 above. For example, the encoding means1031 and transmitting means 1033 may generate a bitstream 1014. FIG. 8above illustrates one example of a concrete apparatus structure of FIG.10. Other various structures may be implemented to realize one or moreof the functions of FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 6 and FIG. 8.For example, a DSP may be realized by software.

FIG. 11 is a block diagram illustrating one configuration of anelectronic device 1102 in which systems and methods for buffering abitstream 1114 may be implemented. The electronic device 1102 mayinclude receiving means 1135 and decoding means 1137. The receivingmeans 1135 and decoding means 1137 may be configured to perform one ormore of the functions described in connection with one or more of FIG.1, FIG. 5, FIG. 7 and FIG. 9 above. For example, the receiving means1135 and decoding means 1137 may receive a bitstream 1114. FIG. 9 aboveillustrates one example of a concrete apparatus structure of FIG. 11.Other various structures may be implemented to realize one or morefunctions of FIG. 1, FIG. 5, FIG. 7 and FIG. 9. For example, a DSP maybe realized by software.

The term “computer-readable medium” refers to any available medium thatcan be accessed by a computer or a processor. The term“computer-readable medium,” as used herein, may denote a computer-and/or processor-readable medium that is non-transitory and tangible. Byway of example, and not limitation, a computer-readable orprocessor-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can carry or store desired programcode in the form of instructions or data structures and that can beaccessed by a computer or processor. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray® disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.

It should be noted that one or more of the methods described herein maybe implemented in and/or performed using hardware. For example, one ormore of the methods or approaches described herein may be implemented inand/or realized using a chipset, an ASIC, a large-scale integratedcircuit (LSI) or integrated circuit, etc.

Each of the methods disclosed herein comprises one or more steps oractions for achieving the described method. The method steps and/oractions may be interchanged with one another and/or combined into asingle step without departing from the scope of the claims. In otherwords, unless a specific order of steps or actions is required forproper operation of the method that is being described, the order and/oruse of specific steps and/or actions may be modified without departingfrom the scope of the claims.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the systems, methods, and apparatus described herein withoutdeparting from the scope of the claims.

What is claimed is:
 1. An electronic device for encoding a bufferparameter, comprising a first generating circuit configured to generatepicture level parameters; a second generating circuit configured togenerate a sub-picture coded picture buffer (CPB) parameter presentflag, wherein said sub-picture CPB present flag equal to 1 specify thata CPB operate at an access unit level or said sub-picture level; a thirdgenerating circuit configured to generate a sub-picture level bufferparameters if said picture is allowed to be decoded on said sub-picturelevel; and a specifying circuit configured to specify a CPB size,wherein said CPB size is specified by using said picture levelparameters when operating at said access unit level or said CPB size isspecified by using said sub-picture level buffer parameters whenoperating at said sub-picture level.
 2. The electronic device of claim1, wherein said specifying circuit confirms a flag, specifies said CPBsize by using said picture level parameters when said flag equal to 0and specifies said CPB size by using said sub-picture level bufferparameters when said flag equal to
 1. 3. The electronic device of claim1, wherein said sub-picture level buffer parameters are generated ifsaid sub-picture CPB parameter present flag equal to
 1. 4. Theelectronic device of claim 1, wherein said picture level parameters aregenerated independently of said sub-picture CPB parameter present flag.5. The electronic device of claim 1 generating a bitstream includingsaid picture level parameters, sub-picture CPB parameter present flagand sub-picture level buffer parameters.
 6. The electronic device ofclaim 1, wherein said sub-picture level buffer parameters are a bufferscale parameter and a buffer size parameter.